The Carroll County Planning and Zoning Commission gave preliminary approval yesterday to two subdivisions it had previously rejected because of school crowding.

The votes to approve two more lots in the Re-Jo Estates subdivision in Reese and 30 lots in the Jenna Estates subdivision PTC in South Carroll were unanimous.

And in the case of Jenna Estates, slightly reluctant.

The portion of the Jenna Estates subdivision that would be built first is in a conservation zone east of the Springfield Hospital Center in Sykesville and north of Arrington Road next to Patapsco Valley State Park. As a rule, only one house per 3 acres is allowed in a conservation zone.

But the law allows homes in conservation zones to be clustered -- one house per 2 acres -- to preserve a large tract of open space. And that is exactly what the developer proposes.

The open space, which may be owned in common by the residents or deeded to the county, has been accepted by the county as a source of future ground water for the Freedom area water system.

Ironically, the water would not serve the 90-acre parcel approved for a subdivision yesterday. The 30 homes on that site would be served by well and septic systems, even though they are adjacent to a water and sewer service area.

That did not sit well with commission Chairman Thomas G. Hiltz of Woodbine, who was told he was correct in his assumption that well and septic systems harm parkland more than public water and sewer service.

"What planning principle are we following when we have water and sewer [service] nearby and we're allowing well and septic" instead, he asked.

K. Marlene Conaway, Carroll's deputy planning director, said that the property is outside the county's planned water and sewer service area and that 2-acre lots would be big enough to handle individual septic systems

"I'm very concerned" that when a large development is proposed next to a water and sewer service area it cannot connect to that service, Hiltz said.

As chairman of the commission, Hiltz doesn't vote except in the case of a tie. He did not vote on the project.